Terrabon proves biomass-to-fuel process

By Anna Austin
Posted July 28, 2009, at 12:59 p.m. CST

Terrabon LLC has produced high-octane green gasoline from biomass at its advanced biofuels research facility in Bryan, Texas, using its MixAlco pretreatment and fermentation technology.

In April, Terrabon received the first installment of an equity infusion for an undisclosed amount, from Texas-based oil refiner and lead Terrabon investor Valero Energy Corp., which owns and operates 16 oil refineries in the U.S. Its subsidiary, Valero Renewable Fuels, recently became the owner of some of bankrupt ethanol producer VeraSun Energy Corp assets, including five ethanol production facilities and a development site.

Terrabon said it intended to use the funds to accelerate commercial deployment of its MixAlco technology, an acid fermentation process which converts biomass materials such as municipal solid waste into chemicals that can be processed to make fuel.

The MixAlco process works by first treating the feedstock with lime to enhance its digestibility, and then fermenting the biomass using a mixed-culture of microorganisms to produce a mixture of carboxylic acids. Calcium carbonate is added to the fermentation to neutralize the acids to form their corresponding carboxylate salts, which are dewatered, concentrated, dried and thermally converted to ketones. The ketones are hydrogenated to alcohols and refined into renewable gasoline, diesel and jet fuel.

Cesar Granda, Terrabon chief technology officer, said the fuel has a similar distillation profile to the gasoline that's produced in a refinery from the fluid catalytic cracker unit, which represents about 40 percent of the U.S. gasoline supply, but has a sulfur content four times lower and an octane rate that is much higher.

The company recently filed an application with the U.S. DOE for a $25 million grant to construct a 1.3 MMgy biorefinery that would use 55 tons per day of biomass at Valero Energy's refinery in Port Arthur, Texas. Construction of the facility is slated to begin in the first quarter of 2010. The plant is expected to be operating in the second half of 2011.

In commercially deploying the technology, Terrabon believes a plant 5.5 MMgy plant can be built for about $2 per gallon, based on a capacity of 220 dry tons per day of organic feedstock and using post-sorted municipal sold waste delivered at a price of $10 per ton.

The company plans to license and joint venture the MixAlco technology, originally developed at Texas A&M University, with companies that control existing infrastructure for biomass collection and transportation.